This change is made up of a number of tightly coupled
changes:
- Deprecate the use of the USE_BOOTLOADER command-line
option. It is now hard-coded in each Makefile.
Overriding it on the command line is not allowed.
- Split apart the memory declaration and the section
declaration in all linker files (*_memory.ld and
*_sections.ld).
- Describe the split between bootloader and app sections
of flash in each board's _memory.ld file.
- Change program target to selectively erase flash so
that the installed bootloader is preserved across even
JTAG programming operations.
- All elf files are built with debug symbols and are not
stripped. This should help debugging with gdb. The
images programmed on the boards are all .bin files now
which do not include symbols.
